[HackerLank] Recursive Digit Sum - 문제풀이 Description 주어진 숫자를 자리수마다 잘라서 모두 더하는 연산을 반복 한뒤 한자리 숫자를 반환하는 문제입니다. Solution 1. Recursion public static int superDigit(String n, int k) { if(n.length() == 1 && k == 1) return Integer.valueOf(n); long sum = 0; for(int i=0;i 알고리즘/HackerRank 2022. 3. 25. 04:09
[LeetCode] 61. Rotate List - 문제풀이 Description 주어진 링크드리스트를 k만큼 오른쪽으로 로테이션하여 반환하는 문제입니다. Given the head of a linked list, rotate the list to the right by k places. Example 1: Input: head = [1,2,3,4,5], k = 2 Output: [4,5,1,2,3] Example 2: Input: head = [0,1,2], k = 4 Output: [2,0,1] Constraints: The number of nodes in the list is in the range [0, 500]. -100 알고리즘/LeetCode 2022. 3. 11. 13:05
[LeetCode] 2. Add Two Numbers - 문제풀이 Description 주어진 두 링크드 리스트의 역순으로 읽은 숫자의 합을 역순으로 반환하는 문제입니다. You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbers and return the sum as a linked list. You may assume the two numbers do not contain any leading zero, except the number 0 itself. Example 1: Input: l1.. 알고리즘/LeetCode 2022. 3. 10. 20:44
[LeetCode] 82. Remove Duplicates from Sorted List II - 문제풀이 Description 정렬된 링크드 리스트에서 중복되는 값을 가진 노드를 제거하여 반환하는 문제입니다. Given the head of a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. Return the linked list sorted as well. Example 1: Input: head = [1,2,3,3,4,4,5] Output: [1,2,5] Example 2: Input: head = [1,1,1,2,3] Output: [2,3] Constraints: The number of nodes in the list is in th.. 알고리즘/LeetCode 2022. 3. 10. 18:36
[LeetCode] 706. Design HashMap - 문제풀이 Description 해시테이블 라이브러리를 사용하지 않고 HashMap을 구현하는 문제입니다. Design a HashMap without using any built-in hash table libraries. Implement the MyHashMap class: MyHashMap() initializes the object with an empty map. void put(int key, int value) inserts a (key, value) pair into the HashMap. If the key already exists in the map, update the corresponding value. int get(int key) returns the value to which the .. 알고리즘/LeetCode 2022. 3. 8. 19:32
[LeetCode] 56. Merge Intervals - 문제풀이 Description 배열이 주어지면 겹치는 모든 간격을 병합 하고 입력의 모든 간격을 포함하는 겹치지 않는 간격의 배열을 반환합니다 Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input. Example 1: Input: intervals = [[1,3],[2,6],[8,10],[15,18]] Output: [[1,6],[8,10],[15,18]] Explanation: Since intervals [1,3] and .. 알고리즘/LeetCode 2022. 3. 8. 18:18
[LeetCode] 75. Sort Colors - 문제풀이 Description 숫자로 색을 나타내는 요소를 가진 배열을 같은색끼리 인접하도록 onepass로 inplace로 정렬 처리하는 문제입니다. Given an array nums with n objects colored red, white, or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white, and blue. We will use the integers 0, 1, and 2 to represent the color red, white, and blue, respectively. You must solve this problem without usin.. 알고리즘/LeetCode 2022. 3. 8. 17:22
[LeetCode] 15. 3Sum - 문제풀이 Description 주어진 배열에서 서로 다른 요소의 합이 0이 되는 모든 순열을 반환하는 문제입니다. Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0. Notice that the solution set must not contain duplicate triplets. Example 1: Input: nums = [-1,0,1,2,-1,-4] Output: [[-1,-1,2],[-1,0,1]] Example 2: Input: nums = [] Output: [] Exampl.. 알고리즘/LeetCode 2022. 3. 7. 17:07
[Codility] Lesson6. Distinct - 문제풀이 Description 배열 A가 N개의 정수로 구성된 경우 배열 A의 고유 값 수를 반환합니다. that, given an array A consisting of N integers, returns the number of distinct values in array A. For example, given array A consisting of six elements such that: A[0] = 2 A[1] = 1 A[2] = 1 A[3] = 2 A[4] = 3 A[5] = 1 the function should return 3, because there are 3 distinct values appearing in array A, namely 1, 2 and 3. Write an efficient .. 알고리즘/Codility 2022. 3. 5. 21:53
[LeetCode] 392. Is Subsequence - 문제풀이 Description 두 문자열 s와 t가 주어졌을 때 s가 t의 연속이면 true를 반환하고 그렇지 않으면 false를 반환한다. Given two strings s and t, return true if s is a subsequence of t, or false otherwise. A subsequence of a string is a new string that is formed from the original string by deleting some (can be none) of the characters without disturbing the relative positions of the remaining characters. (i.e., "ace" is a subsequence of "a.. 알고리즘/LeetCode 2022. 3. 4. 16:44
[LeetCode] 338. Counting Bits - 문제풀이 Description 정수가 주어지면 각 ( ) 에 대해 의 이진 표현에서 의 수가 되도록 길이 의 배열n 을 반환 합니다 Given an integer n, return an array ans of length n + 1 such that for each i (0 알고리즘/LeetCode 2022. 3. 2. 00:58
[LeetCode] 228. Summary Ranges - 문제풀이 Description 정렬된 유일한 값을 가지는 배열이 주어졌을때 배열의 모든 숫자를 정확히 포함 하는 가장 작은 정렬된 범위 목록을 반환 합니다 . You are given a sorted unique integer array nums. Return the smallest sorted list of ranges that cover all the numbers in the array exactly. That is, each element of nums is covered by exactly one of the ranges, and there is no integer x such that x is in one of the ranges but not in nums. Each range [a,b] in the.. 알고리즘/LeetCode 2022. 2. 28. 19:11
[LeetCode] 39. Combination Sum - 문제풀이 Description 주어진 배열에서 중복이 허용되는 조합의 합이 target이 되는 모든 요소를 반환하는 문제입니다. 요소의 값이 같고 순서가 다른 것은 동일한 조합으로 칩니다. Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. You may return the combinations in any order. The same number may be chosen from candidates an unlimited number of times. Two .. 알고리즘/LeetCode 2022. 2. 17. 12:15
[LeetCode] 24. Swap Nodes in Pairs - 문제풀이 Description 인접한 두개의 노드끼리 swap하여 반환하는 문제입니다. Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i.e., only nodes themselves may be changed.) Example 1: Input: head = [1,2,3,4] Output: [2,1,4,3] Example 2: Input: head = [] Output: [] Example 3: Input: head = [1] Output: [1] Constraints: The number of .. 알고리즘/LeetCode 2022. 2. 16. 11:13
[LeetCode] 78. Subsets - 문제풀이 Description Given an integer array nums of unique elements, return all possible subsets (the power set). The solution set must not contain duplicate subsets. Return the solution in any order. Example 1: Input: nums = [1,2,3] Output: [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]] Example 2: Input: nums = [0] Output: [[],[0]] Constraints: 1 알고리즘/LeetCode 2022. 2. 13. 22:33
[LeetCode] 144. Binary Tree Preorder Traversal - 문제풀이 Description 전위 순회(preorder-traversal)하며 값을 읽어 List에 순서대로 넣어 반환하는 문제입니다. Given the root of a binary tree, return the preorder traversal of its nodes' values. Example 1: Input: root = [1,null,2,3] Output: [1,2,3] Example 2: Input: root = [] Output: [] Example 3: Input: root = [1] Output: [1] Constraints: The number of nodes in the tree is in the range [0, 100]. -100 right 순으로 전위 순회(preorder-traver.. 알고리즘/LeetCode 2022. 1. 27. 16:32
[LeetCode] 1305. All Elements in Two Binary Search Trees - 문제 풀이 Description Given two binary search trees root1 and root2, return a list containing all the integers from both trees sorted in ascending order. Example 1: Input: root1 = [2,1,4], root2 = [1,0,3] Output: [0,1,1,2,3,4] Example 2: Input: root1 = [1,null,8], root2 = [8,1] Output: [1,1,8,8] Constraints: The number of nodes in each tree is in the range [0, 5000]. -10^5 알고리즘/LeetCode 2022. 1. 26. 15:30
[LeetCode] 203. Remove Linked List Elements - 문제풀이 Description 주어진 LinkedList에서 val값과 일치하는 노드를 제거한 후 반환합니다. Given the head of a linked list and an integer val, remove all the nodes of the linked list that has Node.val == val, and return the new head. Example 1: Input: head = [1,2,6,3,4,5,6], val = 6 Output: [1,2,3,4,5] Example 2: Input: head = [], val = 1 Output: [] Example 3: Input: head = [7,7,7,7], val = 7 Output: [] Constraints: The number o.. 알고리즘/LeetCode 2022. 1. 25. 21:38
[LeetCode] 121. Best Time to Buy and Sell Stock - 문제풀이 Description 주어진 일자별 주식 가격이 기재된 배열에서 가장 큰 이익을 남길 수 있는 경우의 수를 계산하여 반환하는 문제입니다. You are given an array prices where prices[i] is the price of a given stock on the ith day. You want to maximize your profit by choosing a single day to buy one stock and choosing a different day in the future to sell that stock. Return the maximum profit you can achieve from this transaction. If you cannot achieve any .. 알고리즘/LeetCode 2022. 1. 20. 23:33
[LeetCode] 557. Reverse Words in a String III - 문제풀이 Description 공백으로 단어들이 구분되어 있는 문자 배열의 각 단어를 반전시키는 문제입니다. Given a string s, reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Example 1: Input: s = "Let's take LeetCode contest" Output: "s'teL ekat edoCteeL tsetnoc" Example 2: Input: s = "God Ding" Output: "doG gniD" Constraints: 1 알고리즘/LeetCode 2022. 1. 20. 17:05
